However, the fluid outside the axon has a positive charge. Due to the different charges of the outside and inside of the axon, the axon is polarized. When a neuron is “fired”, several events take place to create an electrical impulse called an action potential. Sodium ions, which have a positive charge (Na+), enter the axon. This process depolarizes the axon, which changes the electrical charge inside the axon from negative to positive.
D1; Analyse the role of the phospholipid bilayer in terms of the movement of materials into and out of cells The phospholipid bilayer is the structure which surrounds a cell, this plasma membrane is made up of two layers of phospholipids; these are the intracellular layer, which is at the bottom, and the extracellular layer which is at the top (Wisegeek.com/bilayer. 2011). The mosaic model shows that the phospholipids are arranged in shapes like heads and tails, the polar heads are made up of glycerol, phosphate and nitrogen and the non-polar tails are made up of fatty acid chains (Wisegeek.com/bilayer. 2011). The polar heads will interact with water as they are hydrophilic, though the tails/fatty acids are never exposed to water therefore they are hydrophobic (Wisegeek.com/bilayer.
What is the main difference between osmosis and diffusion. Osmosis transports through the membrane of an object while diffusion spreads across an object. 4. Why is iodine called an indicator? It indicates color when in contact with starch.
UNIVERSITY OF SHARJAH COLLEGE OF MEDICINE MUSCLOSKELETAL UNIT PHYSIOLOGY PRACTICAL HANDOUT PREPARED BY: DR SUNDUS AL-OMAR ACADEMIC YEAR (2011-2012) Nerve Conduction Velocity Theory background The nerve impulse is a wave of depolarization immediately followed by a wave of repolarization, collectively called an action potential, occurring on the plasma membrane of a nerve fiber. Changes in ion conductance across the nerve fiber membrane are responsible for the initiation and propagation of the action potential. Experimentally, these changes can be the result of electrical current applied through electrodes. Once initiated, an action potential is usually propagated without decrement in amplitude or velocity along the plasma membrane of a nerve fiber. In the peripheral nervous system, nerve fibers of various diameters and functions (motor and sensory) are bundled together by connective tissue to form nerves.
Neurones also have a sodium-potassium pump embedded into the neurone membrane, which allows for the neurone’s resting potential to be maintained. A similar pump that is on the cristae of the mitochondria, called the ATP synthase pump, which allows for the production of ATP during respiration. Hydrogen ions from the electron transport chain are diffused into the intermembrane space between the cristae and outer membrane of the mitochondria, creating a concentration gradient, so H+ ions rush through the pump, joining ADP and Phosphate. To use the ATP, another pump (ATPase), ATP binds to the carrier and
A hypothesis for the experiment states that solutions with charged particles are going to conduct an electrical charge whereas solutions with molecular particles will not. There may be a direct correlation between the number of charged particles and the conductivity of the solution. Results Table 1 Substance | Conductivity (μs/cm) | TDS (mg/L) | Sodium chloride (NaCl) | 5432 | 3259.2 | Calcium chloride (CaCl2) | 9127 | 5476.2 | Methanol (CH4O) | 19.09 | 11.454 | Ethanol (C2H6O) | 19.09 | 11.454 | Sucrose (C12H22O12) | 19.09 | 11.454 | Glucose (C6H12O6) | 19.55 | 11.73 | Freshwater | 2826 | 1695.6 | Saltwater | 13800 | 8280 | Tap water | 429.6 | 257.76 | Bottled water | 19.09 | 11.454 | Distilled water | 19.09 | 11.454 | Sports drink | 2855 | 1713 | Figure 1 Table 2 Substance | Conductivity (μs/cm) | TDS (mg/L) | Methanol | 19.09 | 11.454 | Ethanol | 19.09 | 11.454 | Sucrose | 19.09 | 11.454 | Glucose | 19.55 | 11.73 | Tap water | 429.6 | 257.76 | Bottled water | 19.09 | 11.454 | Distilled water | 19.09 | 11.454 | Figure 2 Discussion and conclusion Checking for the presence of charged particles can test solution purity. Particles, in relation to this experiment, come in two forms: molecular and ionic. Molecular compounds are ones, which have shared electrons between the atoms and do not carry an overall charge for the molecule.
Neurotransmitters (NT) act as chemical messengers in the body. Specifically, they function to transmit signals from a neuron to a target cell across a potential space known as a synapse, or synaptic cleft. In effect, this allows one nerve cell to communicate with a second nerve cell. Some common neurotransmitters are acetylcholine, norepinephrine, dopamine, serotonin and gamma aminobutyric acid (GABA). Acetylcholine and norepinephrine are excitatory neurotransmitters while dopamine, serotonin, and GABA are inhibitory (Kau-Nu, 2011).
That is how your body parts interacts and communicate with each other. Neurons communicate by releasing neurotransmitters which fits on a receptor of another neuron close by. There are axons grouped together like a bunch of electrical wire that we call our nerves. A resting neuron has a partial barrier around the cell called a membrane. It protects the fluids inside and outside the neuron.
A mixture of Br-, Cl- and PO43- ions was subjected to an anionic column packed with polym-N(CH3)3+OH-, eluted with 9mM sodium carbonate. (i) Arrange the above analyte ions in order of increasing retention time in the anionic column. (3 marks) (ii) Describe how the analyte ions were separated in the anionic column according to order of retention time answered in part (2)(i). (8 marks) 3. An unknown compound is irradiated with an excitation photon.
Introduction Biological membranes are selectively permeable allowing molecules to move across by means of osmosis and diffusion. The ability of a molecule to move across the membrane depends on charge and size of the molecule and the concentration of molecules on either side of the membrane. In this experiment two types of membrane transport will be studied: osmosis and diffusion. This experiment will also investigate how surface area to volume ratio effects the amount of molecules that can diffuse across the plasma membrane (Biology Department. 2012).